1. Field of Invention
The present invention relates to a casement window, and more particularly to a casement window with multi-angle locking window sash which has a multi-angle locking function.
2. Description of Related Arts
In order to guard against theft, people usually close and lock the housing windows while going out or sleeping. Therefore, as no flowing and fresh air exists in the housing, the housing is sweltering and smelly. In order to solve this problem, anti-theft guardrails welded by steel bars appear and become popular. As the anti-theft guardrails are usually installed outside windows, people indoors can not escape from the windows when emergency situation such as fire occurs. In addition, the anti-theft guardrails also constitute a fire barrier and cause a lot of trouble to fire services. Further, since casement windows generally do not include a locking device, the window sashes are easy to be opened or closed violently by strong wind to cause dangers.
Due to significant side effects existing in installing the anti-theft guardrails, people utilize various alarm devices to guard against theft. Currently, the most widely-used alarm device by people is a pyroelectric infrared detector installed on the windows. When someone is invading, the pyroelectric infrared detector detects infrared thermal given off by human body and generates an alarming signal. However, the device is easy to be affected by changes of external factors such as environment, climate and pets and generates false alarms, which has a serious impact on the normally daily life of people.